Dynamo-electric machine



J. D. WALLACE ET AL 5,750,446 nYNAMo ELECTRIG MACHINE March 11, 1930.

Filed Feb. 27. 1928 Patented Mar. 11, 1930 UNITED STATES 4PATENT OFFICE JOHN D. WALLACE AND CLIFFORD H. LANDIS, OE;I CHICAGO, ILLINOIS, ASSIGNORS '.130v

J. D. WALLACE n COMPANY, F CHICAGO, ILLINOIS, A` CORPORATION OF ILLINOIS nYNArro-i-:Lncrnrc MACHINE i Application filed February 27, 1928. Serial No. 257,471.

This invention relates to power machines, particularly electric motors, and more especially to those which are designed compactly as direct connected electric motor driven units, such for instance as mortisers and the like. The improvements herein referred to reside in the head or tool operating part, and more specifically the motor, as distinct from the work holding part. rihe main objects of the invention are to provide improved means for protecting the machine, especially the motor with its commutator and bearings, from. dust; and to provide improved means for controlling the flow, distribution, and drainage of lubricating oil. The motor must be vertically axled substantially to accommodate the lubricating feature, but the filter is fully eective for any and all positions.

An illustrative embodiment of this invention is shown by the accompanying drawings in which:

Figure 1 is a side elevation of the machine as a whole.

F ig. 2 is an enlarged and somewhat conventionalized view of the combined motor and tool holder, mainly in vertical axial'section.

Fig. 3 is a further enlarged view of the air filter or hood for the motor.

Fig. 4 is a greatly magnified detail of the filter fabric.

A:[n the construction shown in the drawings, the motor M is equipped with ltering and oiling means embodying ourinvention and hereinafter described. These are well shown in Fig. A2. rlhe device as a whole is of portable design and comprises a combination motor and tool head 1 mounted on\an upright frame 2 adaptedA for ready movement on the floor as by means of casters or the like. On the front of said frame, beneath the head 1 is a table 3 equipped with vscrew and hand wheel means 4 adapted for moving the table forwardly and backwardly and a hand wheel 5 adapted and arranged to operate the upright screw 6 for raising and lowering the table.

rlhe head 1 is provided on its rear side with supporting arms 7 and 8 which are secured to upright slidablemeans, not shown, extending downward in the frame 2 and communivmotor through the two-conductor cable 10,

having a plug 11 at its outer end, the inner end of the cable being connected at 12 to the upper end of the head 1 adjacent to the manual snap switch 13.

The lower part of the head 1 is closed, except at its lower conoidal tip, and is made in the form of a cast metal shell 14 with a motor supporting spider 14 integral therewith.

The upper part of the head 1, however, is of open cast metal construction to admit air downwardly for Ventilating the motor and adjacent parts, and is provided with an air filter in the form of a flexible strainer 15 made preferably of a loosely woven or knitted fabric having an abundance of loose fibers properly arranged to entrap the dust par-V ticles as will be more fully explained.

rlhe air admitted through the filter 15 passes downward through the air-gap 20 between the motor armature 21 and the field members 22, thence past the fan 23, through the lower spider 14 and out through the downward nozzle like apertures 25 adjacent to the central tool aperture 26. This downward exit draft serves advantageously to blow away the chips produced by the mortising tool or chisel not shown.

It is to be understood that the tool proper is interchangeable and that as usual in such devices it is carried by a chuck, not shown, which fits on the-tapered end part 30 of the motor shaft 31. The position of the tool, however, Ais indicated at 32 on Fig. 1.

AThe lower end of shaft 31 is carried by bearing rollers and rings therefor arranged to support downward end thrust, as indicated at 33. The upper end `of said shaft is also held by bearing rollers and rings indicated at 36; These upper bearings are carried on a complex form of spider 39 whichois provided with a large central oil cup or chamber 40,

an oil inlet channel 41, an oil catch basin 42 and an excess oil drain 43 leading downward and outward therefrom. In order to prevent oil following down the shaft 31 a horizontal guide ring or oil slinger 45 is secured between an upwardly facing shoulder 46 on the shaft and the inner ring of support 36. This guide rotates with the shaft and theoil is thrown outward centrifugally and is collected in the basin 42 from whence it flows by gravity down the channel 43 and out of the head at 50. The discoidal ring 45, by reason of its high peripheral speed, compa-red with that of the shaft 31, discharges the surplus oil with sufiicient speed to sling it entirely through and across the path of the incoming air from filter 15.

Turning now to the structure of the filter 15 and referring especially to Figures 3 and 4, this member comprises substantially a double walled cylindrical sleeve arranged with one half folded inside the other to produce a form such as indicated in Figure 3. Thisprovides a duplex pocketed strainer, the folded edge part 52 being at the bottom. The free upper edges are bound with tape as at 53 to prevent stretching, the outer layer 54 extending somewhat higher than the inner layer 55 and the edges being designed to fit snugly about the restricted top part 56 of the upper spider member 39 adjacent to the base of switch 13. The lower edge of the filter is stitched all the way around, as at 58, to provide a casing or tunnel 59 for a draw string 60, whereby the lower edge of the filter i may be drawn tightly about the lower edge of the upper spider member adjacent to the field member 22 of the motor, where it is prevented from rising by means of the peripheral rib 62 outstanding on the lower edge of the spider frame. Said tunnel has an opening at 61 for the ends .of the string 60.

This filter is of peculiar structure or weave in that the numerous small fibers 65 are enmeshed medially in the interwoven threads 66 of the fabric, the ends of said fibers all being disposed on one side of the fabric, namely the side which is folded together in the finished filter whereby the two layers consti-y tute a dust collecting pocket 67 filled with numerous closely disposed loose fibers wherein the dust particles are entrapped.

In order to maintainv a filter in efficient working condition, it is removed from time to time, turned inside out and shaken and also washed if desired, whereby the dust is removed and its dust collecting efficiencyv restored. This removal and replacement is rendered convenient by means of the draw string 60, which is normall tied at 61. The turning of the filter inside out may be effected by holding, with one hand, the inner half or part 55, as shown in Fig. 3, and then, with the other hand, taking hold of the edge 53 of the outer part 54, pulling the latter down or toward the edge 52, and so continuing until the parts 54and 55 are pulled into sub` stantially common cylindrical alinement,

and with the fibrous pocket'side facing outwardly. Then after the dust is removed the filter is restored to its normal pocket form by a reverse manipulation of the part 54 relative to part 55.

The fabric used is preferably a rather loosely knitted product, so as to let the air i,

same is true of the commutator brushes and holders therefor. It may be noted that the wire chamber 65iis separated from the oil .chamber by a removable cover 66.

Vhen the device is fullv assembled and ready for use, the operator places his work on the table 3, adjusts the-height of the table by hand wheel 5, then moves the table forward or back by means of hand wheel 4, to properly locate the work relative to the head 1 and then having started the motor by turn-l ing on switch 13 and applying the proper tool to said head, he depresses the foot lever 9 whereby the tool is brought into operative engagement with the work. Whenever desired, the head 1 is elevated by releasing the lever 9. During operation, the fan 23 draws air inward through the filter 15 where all dust is strained out, thence past the motor which is cooled thereby and nally out through the vents 25 and against the work which is effectually cleared of chips.

From time to time the motor may be lubricated by applying oil through the port 41. It is to be understood that the oil chamber 40 may contain an absorbent so that a sucient charge of oil may be stored to last for a considerable period. ln operation the oil seeps down through the bearings 36 and onto the oil slinger 45 from whence it escapes down the channel 43 to the exit port 50.

Eventually the filter 15 becomes more or less clogged with dust entrapped by the fibers 65 in pocket 67 and at such times it is removed and either replaced by another interchangeable filter or preferably turned inside out and cleaned at once and put back in place.

Although but. one specic embodiment of this invention is herein shown and described, it is to be understood that numerous details of the construction shown mag be altered or omitted and that a motor eniv ing and dust filtering features set forth may be used in connection with any appropriate machine without departing from the spirit of the invention as claims.

We claim: i

l. A motor comprising a hollow shell-like odying the oill defined by the following and said frame said filter'and frame and head having operative mechanism therein and means to produce a Ventilating draft therethrough, said head being appropriately apertured to accommodate the necessary inlet and exit of air and being provided with a filter of double walled and fiber lined pocket construction arranged to strain the incoming air and entrap dust particles therein.

2. A power supplying device of the character described comprising an electric motor, a substantially closed head wherein said motor is mounted, inlet and outlet apertures on opposite sides of said motor, and an air filter disposed over the inlet apertures, the inlet part of said head being of conoidal shape and provided with a peripheral rib around its greater periphery, said filter being of loose fabric construction bound with tape around its -inner edge to limit its expansion and provided with a draw string around its larger edge to hold this edge snugly about said rib.

3. In an electric power dust protector device of the character described, a dust filter of double layer woven fabric construction formed with an abundance of dust collecting fibers on the adjacently disposed sides of the filter layers.

4. A cylindro-formed filter of double layer elastic fabric construction adapted to assume a frustro-conoidal shape in use for use on dynamo-electric machines, the inner and outer layers being joined together at the base or large end where the iilter is channeled `and provided with a draw-string, the free edges being bound with tape to prevent stretching.

5. A self ventilated electric motor comprising a stator frame and a rotor, in combination with a cylindro-form filter of yielding knitted construction adapted for pulling on over one end of said frame, said rotor having means to induce a draft inwardly through said filter y being adapted for support independently of its said end.

6. A vertically aXled electric motor comprising a stator frame and a rotor, in combination with a rotary oil slinger on the upper part of the rotor shaft and a yielding cylindro-form filter embracing the upper end of said motor, `said rotor being adapted to induce a downward Ventilating draft through 0 past said oil slinger. Signed at Chicago this 24th day of vFebruary 1928.A v y JOHN D. WALLACE.

CLIFFORD H. LANDIS.

Ventilating 

